Apparatus for the control of highway crossing signals



Feb. 23, 1937. E. M. ALLEN 2,071,995

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSINE SIGNALS Filed June 13, 1936 Sid 12 H I 12p INVENTOR fiafiigllen BY 1 HIS ATTOR N EY Patented Feb. 23, 1937 NHTED STATES PATENT OFFICE APPARATUS FOR THE CONTROL OF HIGH- WAY CROSSING SIGNALS Application June 13, 1936, Serial No. 85,118

10 Claims.

My invention relates to apparatus controlled by a train approaching a highway crossing for governing the operation of a highway crossing signal.

A feature of my invention is the provision of novel and improved apparatus controlled by a train approaching a highway crossing for preventing continued operation of the highway crossing signal in the event the train stops within the control section, and for restart ing the operation of the signal when the train resumes its movement. Other features and advantages of my invention will appear as the specification progresses.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

Apparatus and circuits controlled by a train for preventing a continued operation of a highway crossing signal in the event a train should stop within the control section for the signal and for restarting the operation when the train resumes its movement, are disclosed and claimed in the copending application for United States Letters Patent, Serial No. 58,716, filed January 11, 1936, by James J. Vanhorn for Apparatus for the control of highway crossing signals, and of which application my present application is an improvement.

The accompanying drawing is a diagrammatic view of one form of apparatus embodying the invention.

Referring to the drawing, the reference characters Ia and lb designate the track rails of a stretch of railway over which trafiic normally moves in the direction indicated by an arrow, and which rails are intersected by a highway H. A highway crossing signal S is located adjacent the intersection. This signal S may take any one of several different types of highway crossing signals, and, as here shown, is a flashing light signal. The operation of signals is effected through the medium of a flasher relay FR. The specific structure of relay FR is immaterial, and may be any one of several well-known forms for such relays. It is deemed sumcient for this description to point out that armature 2 of relay PR. is biased to a normal and central position, that is, to the position illustrated in the drawing, and is adapted to swing to the right and to the left to positions indicated by dotted lines when the winding of the relay is energized, the oscillations being at a predetermined rate. Armature 2, when it occupies its normal position, makes engagement with two contacts 3 and 4, breaks engagement with contact 3 when it swings to the right-hand position, and breaks engagement with contact 4 when it swings to the left-hand position. Contact 3 isconnected over wire 5 to lamp 6 of signal S, and contact 4 is connected over wire I with lamp 3 of signal S, the two other terminals of lamps 6 and 8 being connected with the C and negative terminals of any convenient source of current, such as a battery not shown.

. Armature 2 is connected over wire 9 to the positive terminal B of the current source, and which connection will be described hereinafter. Hence with positive current supplied to wire 9 and relay FR. energized, the lamps 6 and 3 of signal S are alternately flashed to display a warning to highway users. The manner of energizing relay FR will also be described later. 7

The track rails Ia; and ID are divided by the usual insulated rail joints to form two track sec tions IT and ?.T which are arranged with their junction adjacent the highway H. The length of section IT is sufiicient to provide a desired minimum warning period of operation of signal S prior to the arrival of a train at the intersection when a train is traveling at the maximum speed for all trains over this stretch of railway, operation of signal S being initiated when the train enters track section IT. I For example, if 120 miles per hour is the maximum speed and 20 seconds is the desired warning period, the section IT would be substantially 3520 feet in length. The section 2T is sufficient in length to provide a similar warning period of the highway crossing signal for trains operating against the normal direction of traffic. e

A wayside station WS where trains frequently stop is located along the section IT. For example, the station WS may be a passenger station, a freight station, or a water station.

The track sections IT and ET are each provided with a track circuit which comprises a source of current such as a battery I0 connected across the rails at one end of the section, and a magnet of an interlocking relay TR, connected across the rails at the other end of the section, the magnet I I of relay TR being associated with track section IT and magnet I2 being associated with section 2T.

A track instrument M is operatively connected with the rail II) at a selected point between the wayside station WS and the highway H. for actuation thereof in response to the wheels of a train passing over the point at which the track instrument is located. The track instrument M is placed far enough in advance of station WS so as not to be actuated by a train prior to its stopping at the station, and is actuated shortly after a train passes the station in its movement toward the highway. This track instrument may take different forms, and is preferably of the type characterized by having a relatively low resistance path when at rest and increasing the resistance of such path when vibrated by the passage of a train. That is, the track instrument M includes a circuit element which is in effect closed when the rail is not vibrated, and which element is in effect opened when the rail is vibrated by a train. This track instrument M may, for example, be a railmicrophone such as disclosed and claimed in United States Letters Patent No. 1,834,077, granted December 1, 1931, to A. J. Sorensen. It is deemed suflicient for this description to point out that such rail microphone comprises an insulated housing which contains two spaced metal electrodes with carbon granules in the space between the electrodes.

' value.

A control relay RP is associated with track instrument M and is controlled over a pick-up circuit and a stick circuit. The pick-up circuit for relay RP includes the B terminal of the current source, front contact I3 of magnet II of relay TR, wire I4, winding of relay RP, and the C terminal of the current source. The stick circuit extends from the B terminal through the electrodes and carbon granules of the track instrument, when the track instrument is a rail microphone, front contact I5, winding of relay RP, and to the C terminal. It is clear that relay RP is normally held energized, that is, when section IT is unoccupied, by its pick-up circuit including the front contact I3 of magnet II, and is placed under the control of the track instrument M when a train enters the section IT and shunts the magnet II to open front contact I3.

The apparatus also includes a time element device which is here shown as a slow pick-up relay TE, the arrangement being such that back contact I6 of relay TE is opened a predetermined time interval, say, for'example, 15 seconds, after the winding of relay TE is energized. The energizing circuit for relay TE extends from the B terminal of the current source over full down contact I1 of magnet I I, front contact I8 of relay RP, winding of relay TE, and to the other terminal C of the source of current. It will be understood that the pick-up time of relay TE may be adjusted to suit the locality at which the apparatus is installed.

In order to describe the operation of the apparatus, I shall first assume that a train traveling in the normal direction of traffic enters operating the relay FR and the signal S. This operating circuit extends from terminal B over full down contact I9, normally closed contact I6 of relay TE, wire 20, winding of relay FR, and to the C terminal, with the result that relay FR is set into operation. Current also flows over this operating circuit up to wire 20, and thence over Wire 9, armature 2, contacts 3 and 4 of relay FR, and to the lamps of signal S in the manner described hereinbefore. It follows that in response to the train entering section IT, the relay RP is placed under the control of track instrument M, the slow pick-up relay TE is energized, and the operation of signal S is initiated. Shortly after the train comes to a stop at station WS, the pick-up period of relay TE has elapsed, and that relay picks up and opens the operating circuit at contact I6, and operation of the signal is stopped. The train, upon resuming its movement away from the station WS soon reaches the location of track instrument M and actuates that instrument to deenergize relay RP, which then remains down until such time as its pick-up circuit is closed. With relay RP deenergized and front contact I8 opened, the relay TE is deenergized and is reset to its normal position with the result that the operating circuit for the signal S is reclosed and operation of the signal restarted. When the train passes over the highway crossing and vacates section IT, the magnet II is reenergized and relay RP is restored to its normal position. The energizing of magnet I I also opens the operating circuit for the signal at back contact I9, and operation of the signal is stopped. This train, upon entering track section 2T to the left of the highway crossing shunts magnet I2 of relay TR, but full down contact ZI of magnet I2 is held open due to the interlocking mechanism of the relay, and operation of the signal S as the train recedes from the crossing through track section 2T is prevented. It is clear that a train operating in the normal direction of traffic at a relatively high speed and not stopping at the station WS would reach the location of the track instrument M and cause release of relay RP prior to the picking up of the slow pick-up relay TE, and, consequently, continuous operation of signal S would be effected by thistrain. A train approaching the crossing through section IT at a relatively low speed might consume in moving from the entrance of the section to the location of track instrument M a time interval greater than the pick-up period of relay TE, and, under such circumstances, operation of the signal S would be stopped and then restarted when the train reaches the location of track instrument M. It will be understood, of course, that the track instrument M is located at suflicient distance from the highway crossing that at least the desired minimum warning period is assured for such low speed trains.

A train operating from left to right against the normal direction of traffic shunts magnet I2 upon entering section 2T, and that magnet is released to close its full down contact ZI and current is supplied to relay FR and to the signal S for operation of the signal. When this train enters section IT and shunts magnet II, the full down contacts I! and I9 are held open and front flagman contact I3 is held closed by the interlocking feature of the relay with the result that the slow pick-up relay TE and the control relay RP as well as the signal S are retained inactive as this train recedes from the crossing through section IT.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, operating means controlled by the track relay to cause operation of the signal when a train approaching the intersection enters the section, control means located at a selected point along the section and placed under the control of a train approaching the intersection by the track relay when the train enters the section, a time element device eifective when energized a predetermined time interval to render said operating means ineffective to operate the signal, means controlled by the track relay to energize said time element device when a train enters the section, and means governed by said control means to deenergize said time element device when a train approaching the intersection reaches said selected point.

2. In combination, a stretch of railway track intersected by a highway and formed into track section, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, operating means controlled by the track relay to cause operation of the signal when a train approaching the intersection enters the section, control means located at a selected point along the section and placed under the control of a train approaching the intersection by the track relay when the train enters the section, a time element device effective when energized a predetermined time interval to render said operating means inefiective to operate the signal, means controlled by the track relay to energize said time element device when a train enters the section, and means governed by said control means to restore the control of the operating means when a train approaching the intersection reaches said selected point.

3. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for said section including a track relay, a highway crossing signal lo,- cated at the intersection, operating means controlled by the track relay to cause operation of the signal when a train approaching the intersection enters the section, a track instrument located at a selected point along the section, a control relay placed under the control of said track instrument by the track relay when a train approaching the intersection enters the section, a time element device eiiective when energized a predetermined time interval to render said operating means inefiective to operate the signal, means controlled jointly by the track relay and said control relay to energize said time element device when a train approaching the intersection enters the section and to discontinue the energizing of said device when the train reaches said selected point and actuates the track instrument.

4. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, operating means controlled by the track relay to cause operation of the signal when a train approaching the intersection enters the section, a track instrument attached to a rail at a selected point along the section, said instrument characterized by increasing its resistance when the rail is vibrated by a train, a control relay, a pick-up circuit for the control relay including a front contact of the track relay, a stick circuit for said control relay including the track instrument, a slow pick-up relay effective when picked up to render the operating means ineifective to operate the signal, and an energizing circuit for said slow pick-up relay including a back contact of the track relay and a front contact of said control relay in series.

5. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, operating means controlled by the track relay to cause operation of the signal when a train approaching the intersection enters the section, a Wayside station located along said section at which trains stop, control means located at a selected point between" the station and the intersection, said control means placed under the control of a train approaching the intersection by the track relay when the train enters the section, a time element device effective when energized a predetermined time interval to stop operation of the signal by said operating means, means controlled by the track relay to energize said device when a train enters the section, and means governed by said control means to render said device ineffective to stop the operation of the signal when a train reaches said selected point, whereby operation of the signal is started when a train enters the section, is stopped if the train stops at the station and is then restarted when the train reaches said selected point.

6. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for the section including a track relay, a highway crossing signal located at the intersection, a wayside station at which trains stop located along the section, control means including a track instrument adapted to be actuated by a train and a normally closed contact which is opened when the instrument is actuated, said instrument positioned along the section to be actuated by a train stopping at the station only after the train resumes its movement toward the intersection, a time element device adapted when energized a predetermined time interval to open a normally closed contact, an energizing circuit for said device including a back contact of the track relay and said contact of the control means, and circuit means for operating the signal including a back contact of the track relay and said contact of the device.

7. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for the section including a track relay, a highway crossing signal located at the intersection, a wayside station at which trains stop located along the section, a track instrument attached to a track rail at a selected point between the station and the intersection, said instrument including a circuit element which is in efiect normally closed and which is in effect opened when the rail is vibrated by a train, a control relay, a stick circuit for said relay including said circuit element, means controlled by the track relay to place the control relayunder the control of said stick circuit when a trainapproaching the intersection enters the section, operating means controlled by the track relay to start operation of the signal when a train approaching the intersection enters the section, means controlled by a train approaching the intersection to render the operating means ineffective to operate the signal a predetermined time interval after the train enters the section, and means governed by the control relay when deenergized to restore the operation of the signal by the operating means.

8. In combination, a stretch of railway track intersected by a highway and formed into a track section, a track circuit for the section including a track relay, a highway crossing signal located at the intersection, a wayside station at which trains stop located along the section,'a track instrument attached to a rail at a selected point between the station and the intersection, said instrument including a circuit element which is normally closed and which is in effect opened when the rail is vibrated by a train, a control relay, a stick circuit including said circuit element and a front contact and. a winding of the control relay as well as a current source whereby the control relay becomes deenergized and remains deenergized when the leading wheel of a train approaching the intersection passes said selected point, operating means controlled by the track relay to start operation of the signal when a train approaching the intersection enters the section, means controlled by a train to stop operation of the signal by the operating means a predetermined time interval after thetrain enters the section, means governed by the control relay when deenergized to restore the operation of the signal by the operating means, and means controlled by the train to reenergize said control relay when the train has vacated the track section.

9. In combination, a stretch of railway track intersected by a highway and formed into a track section on one side of the highway, a track circuit for said section including a track relay, a highway crossing signal located at the intersection, operating means controlled by the track relay to operate the signal when a train approaching the intersection enters the section, a time element device efiective when energized a predetermined time interval to render said operating means ineffective to operate the signal, means controlled by the track relay to energize said device when a train approaching the intersection enters the section, control means located ata selected'point along the section and placed under the control of a train approaching the intersection when the train enters the section, means governed by said control means to deenergize said device when a train approaching the intersection reaches said selected point, and means controlled by a train approaching the intersection from the side oppo site said section to prevent the track relay from energizing said device or placing said control means under the control of a train.

10. In combination, a stretch of railway track intersected by a highway and formed into two track sections which have their junction at the intersection, a track circuit for each section each of which circuits includes a magnet of an interlocking relay, a highway crossing signal located at the intersection, operating means to operate the signal and including a full down contact of a particular one of said magnets, a time element device effective when energized a predetermined time interval to stop operation of the signal by said operating means, means to energize said device including a full down contact or" said one magnet, control means located at a selected point along the section associated with said one magnet and operative when actuated by a train passing said point to deenergize said device, and means to place said control means under the control of a train and including a front contact of said one magnet, whereby said device and control means are retained inactive when a train recedes from the intersection through the section associated with said one magnet due tothe other magnet of the relay being shunted prior to the shunting of said one magnet.

EARL M. ALLEN. 

